"Solr alert core indexing failed" faults are seen due to Solr Database corruption. Specific exceptions messages can be searched from log files to determine solr database corruption. This issue does not have an impact to view alerts at Threat Analyzer or Attack Log but monitors at dashboard might not show data.

The following Knowledge Base articles highlight error messages related to Solr database corruption and how to recreate or re-import the alerts core into the Solr database: